[EDIT] ショートカット機能を適用しました。

src/main/java/com/example/demo/app/domain/model/FixedCostModel.java

@@ -0,0 +1,49 @@
+package com.example.demo.app.domain.model;
+
+import java.util.List;
+
+import com.example.demo.app.infra.entity.CategoryEntity;
+import com.example.demo.app.infra.entity.FixedCostEntity;
+import com.example.demo.app.infra.entity.UserEntity;
+
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+
+@Getter
+@AllArgsConstructor
+public class FixedCostModel {
+
+	private Long fixedCostId;
+
+	private Long userId;
+
+	private Long categoryId;
+	
+	private String fixedCostName;
+
+	private Integer amount;
+	
+	
+	public static FixedCostModel convertFrom(FixedCostEntity fixedCostEntity) {
+		return new FixedCostModel(
+				fixedCostEntity.getFixedCostId(),
+				fixedCostEntity.getUserEntity().getUserId(),
+				fixedCostEntity.getCategoryEntity().getCategoryId(),
+				fixedCostEntity.getFixedCostName(),
+				fixedCostEntity.getAmount());
+	}
+
+	public static List<FixedCostModel> convertFrom(List<FixedCostEntity> fixedCostEntityList) {
+		return fixedCostEntityList.stream().map(FixedCostModel::convertFrom).toList();
+	}
+	
+	public static FixedCostEntity convertTo(FixedCostModel fixedCostModel, UserEntity userEntity, CategoryEntity categoryEntity) {
+		return new FixedCostEntity(
+				fixedCostModel.getFixedCostId(),
+				userEntity,
+				categoryEntity,
+				fixedCostModel.getFixedCostName(),
+				fixedCostModel.getAmount());
+	}
+	
+}

src/main/java/com/example/demo/app/domain/service/FixedCostService.java

@@ -0,0 +1,16 @@
+package com.example.demo.app.domain.service;
+
+import java.util.List;
+
+import com.example.demo.app.domain.model.FixedCostModel;
+
+public interface FixedCostService {
+
+	public List<FixedCostModel> findAllByUserId(Long userId);
+	
+	public FixedCostModel save(FixedCostModel fixedCostModel);
+	
+	public void delete(Long fixedCostId);
+	
+	public FixedCostModel findById(Long fixedCostId);
+}

src/main/java/com/example/demo/app/domain/service/impl/FixedCostServiceImpl.java

@@ -0,0 +1,48 @@
+package com.example.demo.app.domain.service.impl;
+
+import java.util.List;
+
+import org.springframework.stereotype.Service;
+
+import com.example.demo.app.domain.model.FixedCostModel;
+import com.example.demo.app.domain.service.FixedCostService;
+import com.example.demo.app.infra.repository.CategoryRepository;
+import com.example.demo.app.infra.repository.FixedCostRepository;
+import com.example.demo.app.infra.repository.UserRepository;
+
+import lombok.RequiredArgsConstructor;
+
+@Service
+@RequiredArgsConstructor
+public class FixedCostServiceImpl implements FixedCostService{
+
+
+	private final FixedCostRepository fixedCostRepository;
+	private final UserRepository userRepository;
+	private final CategoryRepository categoryRepository;
+	
+	
+	public List<FixedCostModel> findAllByUserId(Long userId) {
+		
+		return  FixedCostModel.convertFrom(fixedCostRepository.findByUserId(userId));
+		
+	}
+	
+	public FixedCostModel save(FixedCostModel fixedCostModel) {
+		
+		return  FixedCostModel.convertFrom(fixedCostRepository.save( FixedCostModel.convertTo(fixedCostModel, userRepository.findById(fixedCostModel.getUserId()).get(), categoryRepository.findById(fixedCostModel.getCategoryId()).get())));
+		
+	}
+	
+	public void delete(Long fixedCostId) {
+		
+		fixedCostRepository.deleteById(fixedCostId);
+		
+	}
+	
+	public FixedCostModel findById(Long fixedCostId) {
+		return  FixedCostModel.convertFrom(fixedCostRepository.findById(fixedCostId).get());
+	}
+	
+	
+}

src/main/java/com/example/demo/app/infra/entity/FixedCostEntity.java

@@ -0,0 +1,42 @@
+package com.example.demo.app.infra.entity;
+
+import jakarta.persistence.Column;
+import jakarta.persistence.Entity;
+import jakarta.persistence.FetchType;
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.GenerationType;
+import jakarta.persistence.Id;
+import jakarta.persistence.JoinColumn;
+import jakarta.persistence.ManyToOne;
+import jakarta.persistence.Table;
+
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+@Entity
+@Table(name = "fixed_cost_t")
+@Data
+@NoArgsConstructor
+@AllArgsConstructor
+public class FixedCostEntity {
+
+	@Id
+	@GeneratedValue(strategy = GenerationType.IDENTITY)
+	@Column(name = "fixed_cost_id")
+	private Long fixedCostId;
+
+	@ManyToOne(fetch = FetchType.LAZY)
+	@JoinColumn(name = "user_id")
+	private UserEntity userEntity;
+
+	@ManyToOne(fetch = FetchType.LAZY)
+	@JoinColumn(name = "category_id")
+	private CategoryEntity categoryEntity;
+	
+	@Column(name = "fixed_cost_name", nullable = false)
+	private String fixedCostName;
+
+	@Column(name = "amount", nullable = false)
+	private Integer amount;
+}

src/main/java/com/example/demo/app/infra/repository/FixedCostRepository.java

@@ -0,0 +1,15 @@
+package com.example.demo.app.infra.repository;
+
+import java.util.List;
+
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.data.jpa.repository.Query;
+
+import com.example.demo.app.infra.entity.FixedCostEntity;
+
+public interface FixedCostRepository extends JpaRepository<FixedCostEntity, Long> {
+
+	@Query("select f from FixedCostEntity f where f.userEntity.userId = :userId")
+	public List<FixedCostEntity> findByUserId(Long userId);
+
+}

src/main/java/com/example/demo/app/presentation/controller/FixedCostController.java

@@ -0,0 +1,120 @@
+package com.example.demo.app.presentation.controller;
+
+import java.time.LocalDate;
+import java.util.ArrayList;
+import java.util.List;
+
+import jakarta.servlet.http.HttpSession;
+
+import org.springframework.stereotype.Controller;
+import org.springframework.ui.Model;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.ModelAttribute;
+import org.springframework.web.bind.annotation.PostMapping;
+
+import com.example.demo.aop.aspect.SessionCheck;
+import com.example.demo.app.domain.model.LoginModel;
+import com.example.demo.app.domain.service.CategoryService;
+import com.example.demo.app.domain.service.FixedCostService;
+import com.example.demo.app.presentation.form.CategoryForm;
+import com.example.demo.app.presentation.form.FixedCostForm;
+
+import lombok.RequiredArgsConstructor;
+
+@Controller
+@RequiredArgsConstructor
+public class FixedCostController {
+
+	private final FixedCostService fixedCostService;
+	private final CategoryService categoryService;
+
+	@SessionCheck
+	@GetMapping("/fixed-cost/list")
+	public String getFixedCostList(
+			HttpSession session, Model model, LocalDate today) {
+		
+		LoginModel loginUser = (LoginModel) session.getAttribute("loginUser");
+		
+		if (today == null) {
+			today = (LocalDate) session.getAttribute("today");
+		}
+		
+		List<FixedCostForm> fixedCostFormList = FixedCostForm.convertFrom(fixedCostService.findAllByUserId(loginUser.getUserId()));
+		
+		fixedCostFormList.forEach(fixedCostForm -> fixedCostForm.setCategoryName(categoryService.findOne(fixedCostForm.getCategoryId()).getCategoryName()));
+		
+		model.addAttribute("fixedCostFormList", fixedCostFormList);
+		
+		model.addAttribute("today", today);
+		
+		return "fixed_cost";
+	}
+	
+	
+	@SessionCheck
+	@GetMapping("/fixed-cost/create")
+	public String getFixedCostCreate(
+			HttpSession session, @ModelAttribute FixedCostForm fixedCostForm, Model model, LocalDate today) {
+		
+		List<CategoryForm> categoryFormList = CategoryForm.convertFrom(categoryService.findAll());
+		
+		List<CategoryForm> expenseList = new ArrayList<CategoryForm>();
+		
+		List<CategoryForm> incomeList = new ArrayList<CategoryForm>();
+		
+		for (CategoryForm categoryForm : categoryFormList) {
+			
+			if (categoryForm.getTransactionType() == 0) {
+				expenseList.add(categoryForm);
+			} else {
+				incomeList.add(categoryForm);
+			}
+			
+		}
+		
+		model.addAttribute("expenseList", expenseList);
+		model.addAttribute("incomeList", incomeList);
+		model.addAttribute("today", today);
+		
+		
+		return "fixed_cost_create";
+	}
+	
+	
+	
+	@SessionCheck
+	@PostMapping("/fixed-cost/create")
+	public String postFixedCostCreate(
+			HttpSession session, @ModelAttribute FixedCostForm fixedCostForm, Model model, LocalDate today) {
+		
+		LoginModel loginUser = (LoginModel) session.getAttribute("loginUser");
+		
+		fixedCostForm.setUserId(loginUser.getUserId());
+		
+		fixedCostService.save(FixedCostForm.convertTo(fixedCostForm));
+		
+		session.setAttribute("today", today);
+		
+		return "redirect:/fixed-cost/list";
+	}
+	
+	
+	@SessionCheck
+	@PostMapping("/fixed-cost/delete")
+	public String postFixedCostDelete(Long fixedCostId, LocalDate today, HttpSession session) {
+		
+		fixedCostService.delete(fixedCostId);
+		
+		session.setAttribute("today", today);
+		
+		return "redirect:/fixed-cost/list";
+	}
+	
+	
+	
+	
+	
+	
+	
+
+}

src/main/java/com/example/demo/app/presentation/controller/TransactionController.java

@@ -20,11 +20,13 @@ import org.springframework.web.bind.annotation.RequestParam;
 import com.example.demo.aop.aspect.SessionCheck;
 import com.example.demo.app.domain.model.LoginModel;
 import com.example.demo.app.domain.service.CategoryService;
+import com.example.demo.app.domain.service.FixedCostService;
 import com.example.demo.app.domain.service.GoalService;
 import com.example.demo.app.domain.service.TransactionService;
 import com.example.demo.app.domain.service.UserService;
 import com.example.demo.app.presentation.form.CategoryForm;
 import com.example.demo.app.presentation.form.Expense;
+import com.example.demo.app.presentation.form.FixedCostForm;
 import com.example.demo.app.presentation.form.GoalForm;
 import com.example.demo.app.presentation.form.Income;
 import com.example.demo.app.presentation.form.TransactionForm;
@@ -40,6 +42,7 @@ public class TransactionController {
 	private final CategoryService categoryService;
 	private final GoalService goalService;
 	private final UserService userService;
+	private final FixedCostService fixedCostService;
 
 	// 一覧画面
 	@SessionCheck
@@ -182,16 +185,23 @@ public class TransactionController {
 	@SessionCheck
 	@GetMapping("/transaction/create")
 	public String createOneGet(@RequestParam(defaultValue = "") LocalDate today,
+			Long fixedCostId,
 			Model model) {
 
 		if (today == null) {
 			today = LocalDate.now();
 		}
+		TransactionForm transactionForm = new TransactionForm();
+		transactionForm.setTransactionDate(today);
+		if (fixedCostId != null) {
+			FixedCostForm fixedCostForm = FixedCostForm.convertFrom(fixedCostService.findById(fixedCostId));
+			transactionForm.setCategoryId(fixedCostForm.getCategoryId());
+			transactionForm.setAmount(fixedCostForm.getAmount());
+			transactionForm.setTransactionType(CategoryForm.convertFrom(categoryService.findOne(fixedCostForm.getCategoryId())).getTransactionType());
+		}
 
 		List<CategoryForm> categoryFormList = CategoryForm.convertFrom(categoryService.findAll());
 
-		TransactionForm transactionForm = new TransactionForm();
-		transactionForm.setTransactionDate(today);
 
 		System.out.println(transactionForm.getCategoryName() + " " + transactionForm.getAmount());
 

src/main/java/com/example/demo/app/presentation/form/FixedCostForm.java

@@ -0,0 +1,55 @@
+package com.example.demo.app.presentation.form;
+
+import java.util.List;
+
+import com.example.demo.app.domain.model.FixedCostModel;
+
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+@Data
+@AllArgsConstructor
+@NoArgsConstructor
+public class FixedCostForm {
+
+	private Long fixedCostId;
+
+	private Long userId;
+
+	private Long categoryId;
+	
+	private String fixedCostName;
+
+	private Integer amount;
+	
+	private String categoryName;
+	
+	
+	public static FixedCostForm convertFrom(FixedCostModel fixedCostModel) {
+		return new FixedCostForm(
+				fixedCostModel.getFixedCostId(),
+				fixedCostModel.getUserId(),
+				fixedCostModel.getCategoryId(),
+				fixedCostModel.getFixedCostName(),
+				fixedCostModel.getAmount(),
+				"");
+	}
+
+
+	public static List<FixedCostForm> convertFrom(List<FixedCostModel> fixedCostModelList) {
+		return fixedCostModelList.stream().map(fixedCostModel -> FixedCostForm.convertFrom(fixedCostModel)).toList();
+	}
+
+	public static FixedCostModel convertTo(FixedCostForm fixedCostForm) {
+		return new FixedCostModel(
+				fixedCostForm.getFixedCostId(),
+				fixedCostForm.getUserId(),
+				fixedCostForm.getCategoryId(),
+				fixedCostForm.getFixedCostName(),
+				fixedCostForm.getAmount());
+	}
+	
+	
+	
+}

src/main/resources/templates/fixed_cost.html

@@ -0,0 +1,66 @@
+<!DOCTYPE html>
+<html xmlns:th="http://www.thymeleaf.org">
+
+<head>
+	<meta charset="UTF-8">
+	<title>固定費詳細</title>
+	<link rel="stylesheet" th:href="@{/css/transaction_detail.css}">
+
+	<link href="https://cdn.jsdelivr.net/npm/bootstrap@5.3.7/dist/css/bootstrap.min.css" rel="stylesheet">
+</head>
+
+<body class="pb-5 pt-5">
+
+	<div th:replace="~{header :: header}"></div>
+	<h1 th:text="${today}"></h1>
+
+	<div>
+		<ul>
+			<li th:each="fixedCostForm : ${fixedCostFormList}" class="transaction-item">
+
+				<div>
+					<p>
+						カテゴリ名：
+						<span th:text="${fixedCostForm.categoryName}"></span>
+						<br>
+						固定費名：
+						<span th:text="${fixedCostForm.fixedCostName}"></span>
+						<br>
+						金額：
+						<span th:text="${fixedCostForm.amount}"></span>
+					</p>
+				</div>
+
+				<div class="transaction-buttons">
+
+					<form th:action="@{/transaction/create}" method="get">
+						<input type="hidden" name="fixedCostId" th:value="${fixedCostForm.fixedCostId}">
+						<input type="hidden" name="today" th:value="${today}">
+						<button type="submit">登録</button>
+					</form>
+
+					<form th:action="@{/fixed-cost/delete}" method="post">
+						<input type="hidden" name="fixedCostId" th:value="${fixedCostForm.fixedCostId}">
+						<input type="hidden" name="today" th:value="${today}">
+						<button type="submit">削除</button>
+					</form>
+
+				</div>
+
+				<hr>
+				<hr>
+			</li>
+		</ul>
+	</div>
+
+
+
+	<form th:action="@{/fixed-cost/create}" method="get">
+		<input type="hidden" name="today" id="today" th:value="${today}">
+		<button type="submit">新規登録</button>
+	</form>
+
+	<div th:replace="~{footer :: footer}"></div>
+</body>
+
+</html>

src/main/resources/templates/fixed_cost_create.html

@@ -0,0 +1,129 @@
+<!DOCTYPE html>
+<html>
+
+<head>
+	<meta charset="UTF-8">
+	<title>Insert title here</title>
+	<link rel="stylesheet" th:href="@{/css/menu.css}">
+
+	<link href="https://cdn.jsdelivr.net/npm/bootstrap@5.3.7/dist/css/bootstrap.min.css" rel="stylesheet">
+
+</head>
+
+<body class="pb-5 pt-5">
+
+	<div th:replace="~{header :: header}"></div>
+
+	<h1>取引登録</h1>
+
+	<form th:action="@{/fixed-cost/create}" th:object="${fixedCostForm}" method="post">
+
+
+		<div>
+			<label for="fixedCostName">固定費名</label>
+
+			<input type="text" id="fixedCostName" th:field="*{fixedCostName}" required>
+		</div>
+
+		<br>
+
+
+
+		<div>
+			<label for="transactionType">収入・支出</label>
+
+			<select id="transactionType">
+
+				<option value="">選択してください</option>
+				<option value="1">支出</option>
+				<option value="2">収入</option>
+
+			</select>
+		</div>
+
+		<br>
+
+		<div>
+			<label for="categoryId">カテゴリ</label>
+
+			<select id="categoryId" th:field="*{categoryId}">
+				<option value="">選択してください</option>
+
+				<option class="expenseListClass" th:each="category : ${expenseList}" th:value="${category.categoryId}"
+					th:text="${category.categoryName}">
+				</option>
+
+				<option class="incomeListClass" th:each="category : ${incomeList}" th:value="${category.categoryId}"
+					th:text="${category.categoryName}">
+				</option>
+			</select>
+
+		</div>
+
+		<br>
+
+		<div>
+			<label for="amount">金額</label>
+
+			<input type="number" id="amount" th:field="*{amount}" min="0" placeholder="金額を入力してください" required>
+		</div>
+
+		<br>
+		<input type="hidden" name="today" id="today" th:value="${today}">
+
+		<button type="submit">登録</button>
+
+	</form>
+
+	<div th:replace="~{footer :: footer}"></div>
+
+	<script>
+		const transactionType = document.getElementById("transactionType");
+		const categoryId = document.getElementById("categoryId");
+
+		const expenseList = document.getElementsByClassName("expenseListClass");
+		const incomeList = document.getElementsByClassName("incomeListClass");
+
+		transactionType.addEventListener("change", function () {
+
+			if (this.value === "1") {
+
+				for (let i = 0; i < expenseList.length; i++) {
+					expenseList[i].style.display = "";
+				}
+
+				for (let i = 0; i < incomeList.length; i++) {
+					incomeList[i].style.display = "none";
+				}
+
+			} else if (this.value === "2") {
+
+				for (let i = 0; i < expenseList.length; i++) {
+					expenseList[i].style.display = "none";
+				}
+
+				for (let i = 0; i < incomeList.length; i++) {
+					incomeList[i].style.display = "";
+				}
+
+			} else {
+
+				for (let i = 0; i < expenseList.length; i++) {
+					expenseList[i].style.display = "none";
+				}
+
+				for (let i = 0; i < incomeList.length; i++) {
+					incomeList[i].style.display = "none";
+				}
+			}
+
+			categoryId.value = "";
+		});
+	</script>
+
+
+
+</body>
+
+
+</html>

src/main/resources/templates/transaction_detail.html

@@ -56,6 +56,10 @@
 		<input type="hidden" name="today" id="today" th:value="${today}">
 		<button type="submit">新規登録</button>
 	</form>
+	<form th:action="@{/fixed-cost/list}" method="get">
+		<input type="hidden" name="today" th:value="${today}">
+		<button type="submit">固定費一覧</button>
+	</form>
 
 	<div th:replace="~{footer :: footer}"></div>
 </body>